rowing a boat and speed

Question

kyle and nick row their boat (at constant speed) 16 miles downstream for 2 hrs, helped by the current. Rowing at the same rate, the trip back against the current takes 8 hrs. Find rate of the current.

Answer 1

distance = rate * time

OR

rate = distance / time

 

the rate is the sum of the rowing speed (RS) and the speed of the current (CS)

 

downstream:

 

RS + CS = 16 /2 = 8 miles/hour

 

Upstream:

 

RS - CS = 16/8 = 2miles/hour

 

Add the 2 equations:

RS + CS = 8

RS - CS =2

2RS = 10

RS = 5

 

CS = 3